Search

Missed hemodialysis (HD) treatments not due to hospitalization have been associated with poor clinical outcomes and related in part to treatment nonadherence. Using data from the Dialysis Outcomes and Practice Patterns Study (DOPPS) phase 5 (2012-2015), we report findings from an international investigation of missed treatments among patients prescribed thrice-weekly HD.Prospective observational study.8,501 patients participating in DOPPS, on HD therapy for more than 120 days, from 20 countries. Longitudinal and cross-sectional analyses were performed based on the 4,493 patients from countries in which 4-month missed treatment risk was5%.The main predictor of patient outcomes was 1 or more missed treatments in the 4 months before DOPPS phase 5 enrollment; predictors of missed treatments included country, patient characteristics, and clinical factors.Mortality, hospitalization, laboratory measures, patient-reported outcomes, and 4-month missed treatment risk.Outcomes were assessed using Cox proportional hazards, logistic, and linear regression, adjusting for case-mix and country.The 4-month missed treatment risk varied more than 50-fold across all 20 DOPPS countries, ranging from 1% in Italy and Japan to 24% in the United States. Missed treatments were more likely with younger age, less time on dialysis therapy, shorter HD treatment time, lower Kt/V, longer travel time to HD centers, and more symptoms of depression. Missed treatments were positively associated with all-cause mortality (HR, 1.68; 95% CI, 1.37-2.05), cardiovascular mortality, sudden death/cardiac arrest, hospitalization, serum phosphorus level 5.5mg/dL, parathyroid hormone level 300pg/mL, hemoglobin level 10g/dL, higher kidney disease burden, and worse general and mental health.Possible residual confounding; temporal ambiguity in the cross-sectional analyses.In the countries with a 4-month missed treatment risk5%, HD patients were more likely to die, be hospitalized, and have poorer patient-reported outcomes and laboratory measures when 1 or more missed treatments occurred in a 4-month period. The large variation in missed treatments across 20 nations suggests that their occurrence is potentially modifiable, especially in the United States and other countries in which missed treatment risk is high.

Background Minimizing clinical complications in patients with advanced chronic kidney disease (CKD) and improving the transition to dialysis therapy and transplantation represents a challenge, requiring reliable evidence regarding the effects of CKD care on outcomes. Study design The CKD Outcomes and Practice Patterns Study (CKDopps) is a new international prospective cohort study designed to describe and evaluate variation in nephrologist-led CKD practices. Setting & participants CKDopps is underway in Brazil, France, Germany, Japan, and the United States. Diverse national samples of nephrology clinics are being recruited based on random selection stratified by geographic region and clinic characteristics. CKDopps aims to enroll 12,200 non-dialysis-dependent patients with CKD (75% and 25% with estimated glomerular filtration rates Predictors Demographic, comorbid condition, laboratory, and treatment-related variables are collected at 6-month intervals; patient-reported data are collected annually and more frequently near the transition to end-stage kidney disease; nephrologist practice surveys are collected annually. Outcomes Outcomes include mortality, end-stage kidney disease, other clinical events (eg, acute kidney injury, hospitalizations, infections, cardiovascular events, and transplant wait-listing), and patient-reported outcomes. Results For the targeted sample size of 12,200 patients and 160 clinics, CKDopps has 80% power to detect HRs of 1.31 for mortality and 1.19 for mortality or transition to end-stage kidney disease. Limitations CKDopps does not capture care provided in settings outside nephrology clinics (eg, primary care) or patients with CKD not receiving medical care. Conclusions CKDopps is designed to characterize nephrology clinic practice variation and identify practices associated with better outcomes, with particular focus on advanced CKD, transition to end-stage kidney disease, and the patient experience. Because data will be collected during routine clinical care in real-world practice, analyses may yield practical readily implementable findings. CKDopps aims to establish a multinational infrastructure for research, collaboration, and ancillary investigation. Additional countries are encouraged to join.

Reading the special report from Weiner et al1 advocating a “volume first” approach for improving clinical outcomes among hemodialysis patients was a pleasure. However, we disagree with the part of this proposal that dialysate sodium concentrations (DNa) should be “set routinely in the range of 134-138 mEq/L.”1(p685)

From Arbor Research Collaborative for Health, Ann Arbor, MI. Originally published online October 21, 2013. Concepts presented in this article are based on data available at the DPM website and may have appeared in resources and media releases distributed by DPM. Address correspondence to Douglas S. Fuller, MS, Arbor Research Collaborative for Health, 340 E Huron St, Ste 300, Ann Arbor, MI 48104. E-mail: doug.fuller@arborresearch.org 2013 by the National Kidney Foundation, Inc. 0272-6386/$36.00 http://dx.doi.org/10.1053/j.ajkd.2013.09.006 The Dialysis Outcomes and Practice Patterns Study (DOPPS) Practice Monitor (DPM) was developed to detect and report on trends in dialysis care before, during, and after implementation of the end-stage renal disease prospective payment system (PPS), which was initiated by the US Centers for Medicare & Medicaid Services (CMS) in January 2011. The DPM is based on a national sample of US hemodialysis facilities, with sampling weighting techniques used to calculate nationally representative statistics. The DPM is updated every 4 months at www.dopps.org/DPM, with data available after a lag period of just 2-4 months. The rationale and methods of the DPM have been described previously and statistics based on the DPM sample have been shown to closely correspond to other published national data. As a continuation of previous publications in AJKD, here we highlight trends in anemia from August 2010 through December 2012. As discussed in previous DPM updates, several changes provided direct impetus for US dialysis centers to change anemia management during this period: the addition of previously separate billable services including erythropoiesis-stimulating agents (ESAs) and intravenous (IV) iron to the composite bundled dialysis payment rate, a revised ESA label approved by the US Food and Drug Administration (FDA) that removed a specific target for hemoglobin (Hb) level (June 2011), and soon after, the discontinuation by the CMS Quality Incentive Program of the payment penalty for Hb levels , 10 g/dL. DPM data reported here reflect an average of 3,504 (range, 2,131-4,191) hemodialysis patients in 96 (range, 74-110) facilities per month over a 29-month period. Data are aggregated across facilities and dialysis organizations; thus, aggregated trends may not reflect trends in individual facilities or dialysis organizations.

A new initiative of the United States (U.S.) Dialysis Outcomes and Practice Patterns Study (DOPPS), the DOPPS Practice Monitor (DPM) provides up-to-date data and analyses to monitor trends in dialysis practice during implementation of the new Centers for Medicare and Medicaid Services (CMS) End-Stage Renal Disease (ESRD) Prospective Payment System (PPS; 2011–2014). We review DPM rationale, design, sampling approach, analytic methods, and facility sample characteristics. Using stratified random sampling, the sample of ~145 U.S. facilities provides results representative nationally and by facility type (dialysis organization size, rural/urban, free-standing/hospital-based), achieving coverage similar to the CMS sample frame at average values and tails of the distributions for key measures and patient characteristics. A publicly available Web report (www.dopps.org/DPM) provides detailed trends including demographic, comorbidity, and dialysis data, medications, vascular access, and quality of life. Findings are updated every 4 months and lagged only 3–4 months. Baseline data are from mid-2010, prior to the new PPS. In sum, the DPM provides timely, representative data to monitor the effects of the expanded PPS on dialysis practice. Findings can serve as an early warning system for possible adverse effects on clinical care and as a basis for community outreach, editorial comment, and informed advocacy.

Previously, the Dialysis Outcomes and Practice Patterns Study (DOPPS) has shown large international variations in vascular access practice. Greater mortality risks have been seen for hemodialysis (HD) patients dialyzing with a catheter or graft versus a native arteriovenous fistula (AVF). To further understand the relationship between vascular access practice and outcomes, we have applied practice-based analyses (using an instrumental variable approach) to decrease the treatment-by-indication bias of prior patient-level analyses.A prospective observational study of HD practices.Data collected from 1996 to 2004 from 28,196 HD patients from more than 300 dialysis units participating in the DOPPS in 12 countries.Patient-level or case-mix-adjusted facility-level vascular access use. OUTCOMES/MEASUREMENTS: Mortality and hospitalization risks.After adjusting for demographics, comorbid conditions, and laboratory values, greater mortality risk was seen for patients using a catheter (relative risk, 1.32; 95% confidence interval, 1.22 to 1.42; P0.001) or graft (relative risk, 1.15; 95% confidence interval, 1.06 to 1.25; P0.001) versus an AVF. Every 20% greater case-mix-adjusted catheter use within a facility was associated with 20% greater mortality risk (versus facility AVF use, P0.001); and every 20% greater facility graft use was associated with 9% greater mortality risk (P0.001). Greater facility catheter and graft use were both associated with greater all-cause and infection-related hospitalization. Catheter and graft use were greater in the United States than in Japan and many European countries. More than half the 36% to 43% greater case-mix-adjusted mortality risk for HD patients in the United States versus the 5 European countries from the DOPPS I and II was attributable to differences in vascular access practice, even after adjusting for other HD practices. Vascular access practice differences accounted for nearly 30% of the greater US mortality compared with Japan.Possible existence of unmeasured facility- and patient-level confounders that could impact the relationship of vascular access use with outcomes.Facility-based analyses diminish treatment-by-indication bias and suggest that less catheter and graft use improves patient survival.

Background Abnormalities in serum calcium, phosphorus, and parathyroid hormone (PTH) concentrations are common in patients with chronic kidney disease and have been associated with increased morbidity and mortality. No clinical trials have been conducted to clearly identify categories of calcium, phosphorus, and PTH levels associated with the lowest mortality risk. Current clinical practice guidelines are based largely on expert opinions, and clinically relevant differences exist among guidelines across countries. We sought to describe international trends in calcium, phosphorus, and PTH levels during 10 years and identify mortality risk categories in the Dialysis Outcomes and Practice Patterns Study (DOPPS), an international study of hemodialysis practices and associated outcomes. Study Design Prospective cohort study. Participants 25,588 patients with end-stage renal disease on hemodialysis therapy for longer than 180 days at 925 facilities in DOPPS I (1996-2001), DOPPS II (2002-2004), or DOPPS III (2005-2007). Predictors Serum calcium, albumin-corrected calcium (CaAlb), phosphorus, and PTH levels. Outcomes Adjusted hazard ratios for all-cause and cardiovascular mortality calculated using Cox models. Results Distributions of mineral metabolism markers differed across DOPPS countries and phases, with lower calcium and phosphorus levels observed in the most recent phase of DOPPS. Survival models identified categories with the lowest mortality risk for calcium (8.6 to 10.0 mg/dL), CaAlb (7.6 to 9.5 mg/dL), phosphorus (3.6 to 5.0 mg/dL), and PTH (101 to 300 pg/mL). The greatest risk of mortality was found for calcium or CaAlb levels greater than 10.0 mg/dL, phosphorus levels greater than 7.0 mg/dL, and PTH levels greater than 600 pg/mL and in patients with combinations of high-risk categories of calcium, phosphorus, and PTH. Limitations Because of the observational nature of DOPPS, this study can only indicate an association between mineral metabolism categories and mortality. Conclusions Our results provide important information about mineral metabolism trends in hemodialysis patients in 12 countries during a decade. The risk categories identified in the DOPPS cohort may be relevant to efforts at international harmonization of existing clinical guidelines for mineral metabolism.

Health-related quality of life (QOL) is an important measure of how disease affects patients' lives. Dialysis patients have decreased QOL relative to healthy controls. Little is known about QOL in patients with chronic kidney disease (CKD) before renal replacement therapy.The Medical Outcomes Study Short Form-36 (SF-36), a standard QOL instrument, was used to evaluate 634 patients (mean glomerular filtration rate [GFR], 23.6 +/- 9.6 mL/min/1.73 m2 [0.39 +/- 0.16 mL/s/1.73 m2]) enrolled in a 4-center, prospective, observational study of CKD. SF-36 scores in these patients were compared with those in a prevalent cohort of hemodialysis (HD) patients and healthy controls (both from historical data). QOL data also were analyzed for correlations with GFR and albumin and hemoglobin levels in multivariable analyses.Patients with CKD had higher SF-36 scores than a large cohort of HD patients (P0.0001 for 8 scales and 2 summary scales), but lower scores than those reported for the US adult population (P0.0001 for 7 of 8 scales and 1 of 2 summary scales). Patients with CKD stage 4 had lower QOL scores than patients with CKD stage 5, although differences were not significant. Hemoglobin level was associated positively with higher mental and physical QOL scores (P0.05) in all individual and component scales except Pain.SF-36 scores were higher in this CKD cohort compared with HD patients, but lower than in healthy controls. GFR was not significantly associated with QOL. Hemoglobin level predicted both physical and mental domains of the SF-36. Longitudinal studies are needed to define at-risk periods for decreases in QOL during progression of CKD.

Benefits in terms of reductions in mortality corresponding to improvements in Kidney Disease Outcomes Quality Initiative (K/DOQI) compliance for adequacy of dialysis dose and anemia control have not been documented in the literature. We studied changes in achieving K/DOQI guidelines at the facility level to determine whether those changes are associated with corresponding changes in mortality.Adjusted mortality and fractions of patients achieving K/DOQI guidelines for urea reduction ratios (URRs;or =65%) and hematocrit levels (or =33%) were computed for 2,858 dialysis facilities from 1999 to 2002 using national data for patients with end-stage renal disease. Linear and Poisson regression were used to study the relationship between K/DOQI compliance and mortality and between changes in compliance and changes in mortality.In 2002, facilities in the lowest quintile of K/DOQI compliance for URR and hematocrit guidelines had 22% and 14% greater mortality rates (P0.0001) than facilities in the highest quintile, respectively. A 10-percentage point increase in fraction of patients with a URR of 65% or greater was associated with a 2.2% decrease in mortality (P = 0.0006), and a 10-percentage point increase in percentage of patients with a hematocrit of 33% or greater was associated with a 1.5% decrease in mortality (P = 0.003). Facilities in the highest tertiles of improvement for URR and hematocrit had a change in mortality rates that was 15% better than those observed for facilities in the lowest tertiles (P0.0001).Both current practice and changes in practices with regard to achieving anemia and dialysis-dose guidelines are associated significantly with mortality outcomes at the dialysis-facility level.

Experimental and some clinical data suggest that metabolic acidosis contributes to poor nutritional status, a strong predictor for mortality in hemodialysis patients. However, recent cross-sectional studies indicate that severe predialysis metabolic acidosis is associated with a greater normalized protein catabolic rate (nPCR) and greater serum albumin levels. Given this controversy, we analyzed data from the Dialysis Outcomes and Practice Pattern Study (DOPPS) for associations between predialysis serum bicarbonate and albumin concentrations, nPCR, and patient risk for mortality and hospitalization.Data from more than 7,000 representative and randomly selected hemodialysis DOPPS patients from France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States were analyzed. Serum bicarbonate (total CO2 ) levels predialysis were corrected to the midweek interdialytic interval.The midweek predialysis serum bicarbonate level averaged 21.9 mEq/L (mmol/L) and correlated inversely with nPCR, serum albumin, and serum phosphorus values. Before and after adjusting for 15 comorbidities, nutrition, and equilibrated Kt/V, a U-curve best represented the association between predialysis serum bicarbonate level and risk for mortality or hospitalization. Patients with midweek predialysis serum bicarbonate levels of 20.1 to 21.0 mEq/L (mmol/L) faced the lowest risk for mortality, whereas those with bicarbonate levels of 21.1 to 22.0 mEq/L faced the lowest risk for hospitalization. Both high (27 mEq/L) and low (or =17 mEq/L) serum bicarbonate levels were associated with increased risk for mortality and hospitalization.Moderate predialysis acidosis seems to be associated with better nutritional status and lower relative risk for mortality or hospitalization than is observed in patients with normal ranges of midweek predialysis serum bicarbonate concentration (approximately 24 mEq/L) or severe acidosis (16 mEq/L).

Background: The prevalence of water-soluble vitamin use among hemodialysis (HD) patients and whether mortality and hospitalization are associated with water-soluble vitamin use by HD patients have not previously been reported. The present study investigates patterns of water-soluble vitamin use among HD patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS) I and evaluates outcomes associated with vitamin use. Methods: The study sample came from the DOPPS I, a prospective observational study of adult HD patients (N = 16,345) randomly selected from 308 representative dialysis facilities in France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States. Time-dependent Cox regression models were used to assess relative risk (RR) for mortality and hospitalization for patients administered water-soluble vitamins versus those not administered water-soluble vitamins. Results: There was large variation by region in the percentage of patients administered water-soluble vitamins: Europe ranged from a low of 3.7% in the United Kingdom to a high of 37.9% in Spain; 5.6% in Japan; and 71.9% in the United States. Patient use of water-soluble vitamins was associated with a substantially and significantly lower risk for mortality (RR, 0.84; P = 0.001). Lower RR for facility-level mortality also was associated with greater water-soluble vitamin use (RR, 0.98; P = 0.05 per 10% more patients administered water-soluble vitamins at the facility). Conclusion: Although only a randomized trial could prove that water-soluble vitamins improve outcomes, use of water-soluble vitamins is a minimal-risk practice pattern associated with improved outcomes in this prospective observational study.

Anemia is common in hemodialysis (HD) patients.Data collected from nationally representative samples of HD patients (n = 11,041) in 2002 to 2003 were used to describe current anemia management for long-term HD patients at 309 dialysis units in 12 countries. Analyses of associations and outcomes were adjusted for demographics, 15 comorbid classes, laboratory values, country, and facility clustering.For patients on dialysis therapy for longer than 180 days, 23% to 77% had a hemoglobin (Hgb) concentration less than 11 g/dL (110 g/L), depending on country; 83% to 94% were administered erythropoietin (EPO). Mean Hgb levels were 12 g/dL (120 g/L) in Sweden; 11.6 to 11.7 g/dL (116 to 117 g/L) in the United States, Spain, Belgium, and Canada; 11.1 to 11.5 g/dL (111 to 115 g/L) in Australia/New Zealand, Germany, Italy, the United Kingdom, and France; and 10.1 g/dL (101 g/L) in Japan. Hgb levels were substantially lower for new patients with end-stage renal disease, and EPO use before ESRD ranged from 27% (United States) to 65% (Sweden). By patient, EPO use significantly declined with greater Hgb concentration (adjusted odds ratio, 0.61 per 1-g/dL [10-g/L] greater Hgb level; P0.0001), as did EPO dosage. Case-mix-adjusted mortality and hospitalization risk declined by 5% and 6% per 1-g/dL greater patient baseline Hgb level (Por = 0.003 each), respectively. Furthermore, patient mortality and hospitalization risks were 10% to 12% lower for every 1-g/dL greater facility mean Hgb level. Patients were significantly more likely to have Hgb levels of 11 g/dL or greater (or =110 g/L) if they were older; were men; had polycystic kidney disease; had greater albumin, transferrin saturation, or calcium levels; were not dialyzing with a catheter; or had lower ferritin levels. Facilities with greater intravenous iron use showed significantly greater facility mean Hgb concentrations. Mean EPO dose varied from 5,297 (Japan) to 17,360 U/wk (United States). Greater country mean EPO doses were significantly associated with greater country mean Hgb concentrations. Several patient characteristics were associated with greater EPO doses. Even in some countries with high intravenous iron use, 35% to 40% of patients had a transferrin saturation less than 20% (below guidelines).These findings indicate large international variations in anemia management, with significant improvements during the last 5 years, although many patients remain below current anemia guidelines, suggesting large and specific opportunities for improvement.

Several observational studies reported lower mortality risk among hemodialysis patients treated with doses greater than the standard dose. The present study evaluates, with observational data, the secondary randomized Hemodialysis (HEMO) Study finding that greater dialysis dose may benefit women, but not men.Data from 74,120 US hemodialysis patients starting end-stage renal disease therapy were analyzed. Patients were classified into 1 of 5 categories of hemodialysis dose according to their average urea reduction ratio (URR), and their relative risk (RR) for mortality was evaluated by using Cox proportional hazards models. Similar analyses using equilibrated Kt/V were completed for 10,816 hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS) in 7 countries.For both men and women, RR was substantially lower in the URR 70%-to-75% category compared with the URR 65%-to-70% category. Among women, RR in the URR greater-than-75% category was significantly lower compared with the URR 70%-to-75% group (P0.0001); however, no further association with mortality risk was observed for the greater-than-75% category among men (P = 0.22). RR associated with doses greater than the Kidney Disease Outcomes Quality Initiative guidelines (URRor = 65%) was significantly different for men compared with women (P0.01). Similar differences by sex were observed in DOPPS analyses.The agreement of these observational studies with the HEMO Study supports the existence of a survival benefit from greater dialysis doses for women, but not for men. Responses to greater dialysis dose by sex deserve additional study to explain these differences.

Background: In the United States, an association between mortality risk and ethnicity has been observed among hemodialysis patients. This study was developed to assess whether health-related quality of life (HRQOL) scores also vary among patients of different ethnic backgrounds. Associations between HRQOL and adverse dialysis outcomes (ie, death and hospitalization) also were assessed for all patients and by ethnicity. Methods: Data are from the Dialysis Outcomes and Practice Patterns Study for 6,151 hemodialysis patients treated in 148 US dialysis facilities who filled out the Kidney Disease Quality of Life Short Form. We determined scores for three components of HRQOL: Physical Component Summary (PCS), Mental Component Summary (MCS), and Kidney Disease Component Summary (KDCS). Patients were classified by ethnicity as Hispanic and five non-Hispanic categories: white, African American, Asian, Native American, and other. Multiple linear regression models were used to estimate differences in HRQOL scores among ethnic groups, using whites as the referent category. Cox regression models were used for associations between HRQOL and outcomes. Regression models were adjusted for sociodemographic variables, delivered dialysis dose (equilibrated Kt/V), body mass index, years on dialysis therapy, and several laboratory/comorbidity variables. Results: Compared with whites, African Americans showed higher HRQOL scores for all three components (MCS, PCS, and KDCS). Asians had higher adjusted PCS scores than whites, but did not differ for MCS or KDCS scores. Compared with whites, Hispanic patients had significantly higher PCS scores and lower MCS and KDCS scores. Native Americans showed significantly lower adjusted MCS scores than whites. The three major components of HRQOL were significantly associated with death and hospitalization for the entire pooled population, independent of ethnicity. Conclusion: The data indicate important differences in HRQOL among patients of different ethnic groups in the United States. Furthermore, HRQOL scores predict death and hospitalization among these patients. Am J Kidney Dis 41:605-615. © 2003 by the National Kidney Foundation, Inc.

End-stage renal disease (ESRD) attributed to renovascular disease (RVD-ESRD) has been incompletely characterized. We determined incidence trends, clinical features, prior treatment, and survival of patients with RVD-ESRD using the US Renal Data System database. Primary causes of ESRD were assessed in patients starting ESRD therapy during 1991 to 1997. The incidence of RVD-ESRD increased from 2.9/10(6) per year (1.4% of new ESRD cases) to 6.1/10(6) per year (2.1%). The annualized increase was 12.4% per year. This is a greater rate of increase than for ESRD from diabetes mellitis (DM-ESRD; 8.3% per year) and ESRD overall (5.4% per year). The risk for RVD-ESRD versus other-cause ESRD correlated positively with age (odds ratio [OR], 1.7 per 10-year increment; P < 0.0001) and male sex (OR, 1.2; P < 0.0001) and negatively with black (OR, 0.17; P < 0.0001), Asian (OR, 0.29; P < 0.0001), and Native American race (OR, 0.31; P < 0.0001). The unadjusted prevalence of coronary heart disease, cerebrovascular disease, and peripheral vascular disease was greater in patients with RVD-ESRD versus other-cause ESRD (P < 0.001). Of patients with RVD-ESRD, 5% underwent revascularization in the 2 years before ESRD compared with 0.5% of patients with other-cause ESRD, including DM-ESRD. Adjusted for age, race, sex, comorbidity, and laboratory values, the survival of patients with RVD-ESRD was similar to that for patients with other-cause ESRD (risk ratio, 1.01; P = 0.5). These findings suggest that RVD-ESRD is increasing faster than other-cause ESRD and is not independently associated with an increased mortality risk. Strategies may exist to prevent progression to ESRD and merit priority for further study.

Hemodialyzer reuse is commonly practiced in the United States. Recent studies have raised concerns about the mortality risk associated with certain reuse practices. We evaluated adjusted mortality risk during 1- to 2-year follow-up in a representative sample of 12,791 chronic hemodialysis patients treated in 1,394 dialysis facilities from 1994 through 1995. Medical record abstraction provided data on reuse practice, use of bleach, dialyzer membrane, dialysis dose, and patient characteristics and comorbidity. Mortality risk was analyzed by bootstrapped Cox models by (1) no reuse versus reuse, (2) reuse agent, and (3) dialyzer membrane with and without the use of bleach, while considering dialysis and patient factors. The relative risk (RR) for mortality did not differ for patients in reuse versus no-reuse units (RR = 0.96; 95% confidence interval [CI], 0.86 to 1.08; P0.50), and similar results were found with different levels of adjustment and subgroups (RR = 1.01 to 1.05; 95% CI, lower bound0.90, upper bound1.19 each; each P0.40). The RR for peracetic acid mixture versus formalin varied significantly by membrane type and use of bleach during reprocessing, achieving borderline significance for synthetic membranes. Among synthetic membranes, mortality was greater with low-flux than high-flux membranes (RR = 1.24; 95% CI, 1.02 to 1.52; P = 0.04) and without than with bleach during reprocessing (RR = 1.24; 95% CI, 1.01 to 1.48; P = 0.04). Among all membranes, mortality was lowest for patients treated with high-flux synthetic membranes (RR = 0.82; 95% CI, 0.72 to 0.93; P = 0.002). Although mortality was not greater in reuse than no-reuse units overall, differences may exist in mortality risk by reuse agent. Use of high-flux synthetic membrane dialyzers was associated with lower mortality risk, particularly when exposed to bleach. Clearance of larger molecules may have a role.

Hypertension (HTN) and diabetes mellitus (DM) predispose to systemic atherosclerosis with renal involvement. The prevalence of HTN and DM in cadaveric renal donors (affected donors) and the results of transplantation are unknown. We investigated these issues with national data from the US Renal Data System. A total of 4,035 transplants from affected donors were matched 1:1 with unaffected controls according to donor age and race, recipient race, and year of transplantation. Graft and patient survival were estimated. Among the 25,039 solitary renal transplantations performed between July 1, 1994, and June 30, 1997, cadaveric renal transplants from donors with HTN accounted for 15%, and donors with DM, 2%. Programs with 1-year cadaveric renal graft survival rates greater than 90% had 50% less affected donors compared with programs having 1-year cadaveric renal graft survival rates of 85% or less. Compared with donor-age-matched controls, transplants from affected donors were at minimally increased risk for primary nonfunction, delayed graft function, and acute rejection. Three-year graft survival rates were 71% in affected donor organs and 75% in controls (P = 0.001). Compared with controls, duration of HTN was an independent risk factor for graft survival (3-year graft survival rates, 75% versus 65%; relative risk = 1.36 for HTN10 years; P0.001). A substantial fraction of cadaveric renal donors have preexisting HTN. Programs transplanting fewer affected donor kidneys had better than average results. Because the negative impact of donor HTN and DM on transplant outcome was of moderate degree except when the duration of donor HTN was greater than 10 years, use of affected donors should not be discouraged, but graft and patient survival analyses should account for their presence.

This study investigates the role of body size on the mortality risk associated with dialysis dose in chronic hemodialysis patients. A national US random sample from the US Renal Data System was used for this observational longitudinal study of 2-year mortality. Prevalent hemodialysis patients treated between 1990 and 1995 were included (n = 9,165). A Cox proportional hazards model, adjusting for patient characteristics, was used to calculate the relative risk (RR) for mortality. Both dialysis dose (equilibrated Kt/V [eKt/V]) and body size (body weight, body volume, and body mass index) were independently and significantly (P0.01 for each measure) inversely related to mortality when adjusted for age and diabetes. Mortality was less among larger patients and those receiving greater eKt/V. The overall association of mortality risk with eKt/V was negative and significant in all patient subgroups defined by body size and by race-sex categories in the range 0.6eKt/V1.6. The association was negative in the restricted range 0.9eKt/V1.6 (although not generally significant) for all body-size subgroups and for three of four race-by-sex subgroups, excepting black men (RR = 1. 003/0.1 eKt/V; P0.95). These findings suggest that dose of dialysis and several measures of body size are important and independent correlates of mortality. These results suggest that patient management protocols should attempt to ensure both good patient nutrition and adequate dose of dialysis, in addition to managing coexisting medical conditions.

Continuous venovenous hemofiltration (CVVH) or CVVH with additional diffusive dialysis (CVVH-D) has theoretical advantages in treating severe acute renal failure (ARF), but no prospective clinical trials or restrospective comparison studies have clearly shown its superiority over intermittent hemodialysis (HD). To evaluate this question, all 349 adult patients with ARF receiving renal replacement therapy (RRT) at our medical center during 1995 and 1996 were analyzed using multivariate Cox proportional hazards methods. Initial univariate analysis showed the odds of death when receiving initial CVVH to be more than twice those when receiving initial HD (risk for death, 2.03; P0.01). Progressive exclusion of patients in whom the RRT modality might not be open to choice and the risk for death was very high (systolic blood pressure90 mm Hg; total bilirubin level15 mg/dL; or total RRT48 hours) for total RRT left 227 patients in whom the risk for death was 1.09 (95% confidence interval [CI], 0.67 to 1.80; P = 0.72) for initial CVVH, virtually equivalent to the risk for initial HD. Comorbid indicators significantly associated with death or failure to recover renal function included: older age; medical rather than surgical diagnosis; preexisting infection or trauma and liver disease as primary diagnoses; and abnormal bilirubin level or vital signs at initiation of RRT. These results show that the high crude mortality rate of patients undergoing CVVH was related to severity of illness and not the treatment choice itself. With the addition of more inclusive comorbidity data and a broader spectrum of interim outcomes, this type of analysis is a practical alternative to what would almost assuredly be a cumbersome and costly prospective, controlled trial comparing traditional HD with CVVH.

The role of predialysis blood pressure (BP) as a risk factor for the high mortality in chronic hemodialysis (HD) patients has remained controversial. The objective of the current study was to further explore in a national random sample of 4,499 US hemodialysis patients any relationship of systolic or diastolic and predialysis or postdialysis BP with mortality, while considering subgroups of patients and controlling for other patient characteristics and comorbidities. The main finding of this study is the association of a low predialysis systolic BP with an elevated adjusted mortality risk (relative mortality risk [RR] = 1.86 for systolic BP < 110, P < 0.0001). No association with an elevated mortality risk could be observed for predialysis systolic hypertension (RR = 0.98 to 0.99, not significant [NS]), except for an elevated risk of cerebrovascular deaths. Postdialysis systolic BP was associated with an elevated mortality risk both for low and high BP levels as compared with midrange BP. Further evaluation of the elevated mortality risk associated with low predialysis systolic BP indicated similar patterns for both diabetic and nondiabetic subgroups and for patients with and without congestive heart failure (CHF) or coronary artery disease, although it was more pronounced among those with CHF. The level of predialysis fluid excess did not modify these results substantially. The findings from this historical prospective national study do not argue against the treatment of hypertension and suggest greater attention to postdialysis hypertension. The strikingly elevated mortality risk with low predialysis systolic BP suggests that low predialysis BP needs to be viewed with great concern and avoided where possible.

The type of dialysis membrane used for routine therapy has been recently shown to correlate with the survival of chronic hemodialysis patients. We examined whether this effect of dialysis membrane could be explained by differences in dialyzer removal of middle molecules using data from the 1991 Case Mix Adequacy Study of the United States Renal Data System. The sample analyzed included patients who had been treated by hemodialysis for 1 year or more, who were dialyzed with the 19 most commonly used dialyzers in 1991, and for whom delivered urea Kt/V could be calculated from predialysis and postdialysis blood urea nitrogen concentrations. Vitamin B12 (1,355 daltons) was used as a marker for middle molecules, and the clearance of vitamin B12 was estimated based on in vitro data. After adjustments for case mix, comorbidities, and urea Kt/V, the relative risk of mortality for a 10% higher calculated total cleared volume of vitamin B12 was 0.953 (P < 0.0001 v 1.000). Similar results were obtained when middle molecule removal was adjusted for body size. We conclude that both small and middle molecule removal indices appear to be independently associated with the risk of mortality in chronic hemodialysis patients. Differences in mortality when using different types of dialysis membrane may be explained by differences in middle molecule removal.

The past decade has seen substantial improvements in end-stage renal disease (ESRD) outcomes, especially mortality, in the United States. Incidence rates for treated ESRD have doubled for most age groups, probably because of improved survival among high-risk populations, such as patients with diabetes and hypertension. The ESRD patient population is becoming older and has a greater incidence of diabetes because of changes in the types of patients starting treatment. The number of patients added to the waiting list each year for transplants has increased dramatically, whereas the number of transplantations performed annually has remained relatively constant. Although transplantation is consequently less available than before, transplant survival, both of the patient and the graft, has improved dramatically. Length of stay for hospitalizations has decreased. Both dialysis mortality and all ESRD mortality have decreased. It is important to monitor such statistics to try and modify adverse trends in outcomes for patients with ESRD. The ability to monitor patient outcomes through national databases has improved greatly during the last decade. Large-scale population-based studies of practices and outcomes for patients with ESRD offer a potent addition to the previously available arsenal of research tools, which was previously dominated by studies from single or few institutions and more expensive randomized clinical trials.

Details regarding dialysis therapy have been studied by the US Renal Data System (USRDS) in four random samples of US hemodialysis patients during the years 1986 to 1997. During this decade, the delivered dose of hemodialysis therapy has increased by at least 0.2 Kt/V. The frequency of twice weekly dialysis prescription decreased, whereas the duration of each treatment showed only minor changes. A large shift to more biocompatible membranes, particularly to synthetic membranes, was observed. The use of acetate dialysate almost disappeared. Outcomes research by the USRDS showed significantly lower mortality risk associated independently with higher delivered Kt/V, substituted cellulose or synthetic membranes, and bicarbonate dialysate. The projected reduction in mortality risk from these changes in hemodialysis therapy was of a similar magnitude to the observed 14% to 17% reduction in mortality rate during the years 1990 to 1996. National observational studies of dialysis patients may influence the practice of dialysis and lead to improved survival.

Previous studies have revealed that females are less likely than males to receive a renal transplant, the most successful form of treatment of end-stage renal disease (ESRD). The purpose of this study was to determine whether the barrier is to inclusion on the transplant waiting list or to transplantation after being placed on the transplant waiting list. An existing data set was used that included data from the Michigan Kidney Registry, supplemented with data received from the Organ Procurement Agency of Michigan. White and black patients less than 65 years of age and starting ESRD treatment between January 1, 1984, and December 31, 1989, were included. Cox proportional hazards models were used to determine the effect of gender on (1) time to transplantation among all ESRD patients, (2) time from diagnosis of ESRD to inclusion on the transplant waiting list among all ESRD patients, and (3) time from inclusion on the waiting list to transplantation among those patients on the waiting list. Patients were censored at the time of living-related transplantation or death, and were monitored until December 31, 1989. In all, 5,026 incident ESRD patients were included in the study (44.3% female). Of these, 1,626 patients were included on the waiting list (40.1% female); 823 of these received a transplant (37.7% female). Adjusting for age, race, and diagnosis, females were 25% less likely to receive a cadaveric transplant than males (female to male relative rate ratio [RR], 0.75; P0.001). Females with ESRD aged 46 to 55 years and 56 to 65 years were 33% (RR, 0.67; P0.001) and 29% (RR, 0.71; P0.05) less likely to be included on the transplant waiting list, respectively, than their male counterparts. There was no difference in the rate of wait list inclusion among ESRD patients younger than 46 years. Females with ESRD who were included on the transplant waiting list were 26% (RR, 0.74; P0.001) less likely to receive a transplant than males on the waiting list. These results indicate that females are both less likely to be on the transplant waiting list (ages over 45 years) and, once on the list, less likely to receive a transplant (all ages) than males. Further study is necessary to determine the factors contributing to these important barriers to transplantation among females with ESRD.

Several recent retrospective studies of mortality relative to the dose of dialysis have been widely interpreted to indicate that adequate thrice-weekly hemodialysis requires a single pool Kt/V (spKt/V) of at least 1.4 to 1.6 and higher. In these studies, mortality rate has been correlated to the mean delivered spKt/V, (spKt/Vd)m, with coefficient of variation (CV) on the means ranging up to 45%. To evaluate these reported relationships, two large databases were analyzed using population constants to transform urea reduction ratio and spKt/Vd to equilibrated Kt/Vd (eKt/Vd), which expresses dose corrected for treatment time. The eKt/V dose (D) values were correlated to the reported relative risks (RR) of mortality to derive a RR/D function. The RR/D function, derived from these data with stepwise linear regression analysis, is nonlinear, with a steep linear increase in RR for eKt/Vd less than 1.05 and constant RR for eKt/Vdor = 1.05. This RR/D function is mathematically expressed as RR = 1.96 - 1.03(eKt/Vd) (equation 1) when 0.50or = eKt/Vdor = 1.05, and RR = 0.88 (equation 2) when eKt/Vor = 1.05. We show that regression of RR on (eKt/Vd)m with large CV results in overestimation of RR relative to eKt/Vd for individual patients because of extrapolation of the linear relationship beyond the threshold where the slope becomes zero (see equation 2 above). It is concluded that (1) current clinical data indicate that adequate dialysis is provided with eKt/Vd of 1.0 to 1.1 on a thrice-weekly schedule, (2) it is essential to assure that all patients achieve this level of therapy, which is best accomplished using urea kinetic modeling for both prescription and measurement of delivered eKt/Vd, and (3) the current HEMO study is well designed to determine whether higher levels of eKt/Vd will further improve clinical outcome.

To assess differences in the patterns of age-specific black/white comparisons between end-stage renal disease (ESRD) attributed to diabetes (ESRD-DM) and not attributed to diabetes (ESRD-NON-DM), data for subjects 20 to 79 years of age reported by the US Renal Data System as incident cases of ESRD during 1988 to 1991 were analyzed. While the black to white incidence rate ratio (B/W RR) for ESRD-NON-DM peaked in patients before the age of 40 years, the most striking B/W RRs for ESRD-DM were observed in patients older than 40 years. This study also explored evidence supporting the hypothesis that an increased risk of premature death attributed to cardiovascular disease (CVD death) in black patients, alone or in combination with black/white differences in prevalence of diabetes, influences the pattern of age-specific black/white ESRD-DM comparisons. By using estimates of the diabetic population as denominators for the rates, the incidence or ESRD-DM remained much higher in black patients than in white patients for those aged 45 years or above. However, the incidence of ESRD-DM for patients aged below 45 years was found to be significantly (P < 0.05) lower (B/W RR = 0.6) for black male diabetic patients and slightly, yet significantly, higher (P < 0.05; B/W RR = 1.1) for black female diabetic patients than for their white counterparts. Therefore, prevalence of diabetes could not fully explain the pattern of age-specific B/W RR for ESRD-DM.(ABSTRACT TRUNCATED AT 250 WORDS)

It is well known that black Americans have a higher risk for low birth weight (LBW) than white Americans. In addition, blacks are at a higher risk for hypertension (HT), non-insulin dependent diabetes mellitus (NIDDM), and end-stage renal disease (ESRD), particularly ESRD attributed to HT (ESRD-HT) and NIDDM (ESRD-NIDDM). It has been shown that LBW is associated with postpartum anatomic and functional alterations in the kidney and pancreas as well as with progressive renal damage in animals and increased risk for HT and NIDDM during adulthood in humans. Based on these empirical findings, it is here proposed that a greater risk of HT, NIDDM, and ESRD, particularly ESRD-HT and ESRD-NIDDM, in black Americans during adulthood may be partly related to their higher risk of LBW. However, LBW is proposed here as a component factor rather than a sufficient cause or a necessary factor for the development of these diseases. The ultimate contribution of LBW to the black/white disparities regarding HT, NIDDM, and ESRD may depend not only on the black/white differences in LBW but also on the race-specific prevalences of other component factors, both environmental/behavioral and genetic, that may or may not require the presence of LBW to cause each of these diseases.

There is an ongoing discussion in the renal community about how to monitor the treatment of hemodialysis patients in the United States. Comparison of the US patient experience to that of other countries with populations of similar heath status is one way to assess treatment. Another technique involves examining the level of dialysis therapy US patients receive. This paper reviews recent studies which found that the United States has higher mortality than both Japan and Europe and provides additional information as to why those comparisons might be underestimating the mortality differences. We also examine the data on the level of dialysis US patients receive, both as a prescription and as delivered care. We conclude that US patients receive less hemodialysis therapy than their European and Japanese counterparts, and that in general US patients are not receiving the level of dialysis they were prescribed. These factors are correlated with an increased mortality among US hemodialysis patients.

Racial differences in kidney transplantation have received recent attention both in the medical community and in the general public. Most efforts to improve renal transplantation among minority groups have been directed toward cadaveric donation and transplantation. Since evaluation of the comparative trends by race of living related donor (LRD) kidney transplantation have been lacking, we examined trends of LRD transplantation from 1983 through 1990 using national data from the US Renal Data System. The total number of LRDs in blacks did not change during the 8-year period between 1983 and 1990 (198 in 1983 and 197 in 1990). During this same period, the total number of LRDs in whites increased by 11% (1,390 in 1983 and 1,548 in 1990). Rates of LRD transplantation per nontransplanted dialysis patients were consistently lower in blacks and females compared with whites and males, respectively. White males have a fivefold higher rate of LRD transplantation than black males, whereas white females have a fourfold higher rate then black females. When intra racial gender differences were examined, black males were transplanted with LRD kidneys at a rate 20% higher than black females. This difference was present between 1983 and 1989, but was nonexistent in 1990. Among whites, males also had a higher rate of LRD transplantation than females, which gradually decreased from 34% in 1983 to 20% in 1990. In view of the ever-increasing demand for cadaver organs, additional effort in the medical community and society toward increasing LRD transplantation rates represents a more promising approach to increasing organ donation in all groups than a single focus on cadaveric donation. If such efforts are specifically targeted, then described racial and gender disparities in LRD transplantation are likely to be reduced.

We present US county-level maps of the 1983 to 1988 incidence of treated end-stage renal disease (ESRD) among white and nonwhite persons 65 years of age and older (N = 66,129). Recent statistical advances permit the investigation of geographical patterns of unusually low disease incidence. Our maps highlight those US counties which have been determined to have rates of ESRD treatment incidence that are low relative to those of all counties, revealing several interesting geographic patterns. For whites, low rates are found in the Northwest, the Midwest, and the South. Nonwhite rates are seen to be low primarily in the South and Alaska. Low treatment incidence could be due to a combination of (1) low true incidence, (2) lack of access to health care services, (3) insufficient diagnosis and referral, and (4) patients' reluctance to accept ESRD therapy, due to cultural or personal concerns. A state-level regression of elderly rates on those aged 40 to 64 years indicates the variation in treatment incidence among the elderly may be due to factors other than variation in true incidence, which the middle-aged rates reflect more closely. Residual analysis corroborates the visual impression of the maps of low ESRD treatment incidence in several southern states, where referral to dialysis may be as much as 40% lower than the national level. Further research on factors contributing to low treatment incidence, including competing risks, regional lags relative to the national trend to dialyze more elderly patients, and lack of access to health care resources, is indicated.

Analyses were performed on a series of 2,754 dialysis patients between the ages of 20 and 60 years whose end-stage renal disease (ESRD) therapy started in Michigan from 1980 through 1987 with the selection of either center hemodialysis (CH) or continuous ambulatory peritoneal dialysis (CAPD). The dialytic treatment at 6 months after first ESRD therapy was selected as the dialytic "treatment of choice" for each patient. Analyses of subsequent survival showed lower death rates for black patients than for white patients with hypertension (P less than 0.01) and diabetes (P less than 0.01). Death rates increased with patient age more dramatically among glomerulonephritis patients than among the other diagnostic groups (P less than 0.05). Females had significantly lower death rates than did males among diabetic patients (P less than 0.01). While no significant difference was found in average death rates between CH and CAPD (NS), there was a significant difference (P less than 0.05) in the trend in death rates. Death rates among CH patients increased significantly (P less than 0.001) during the study period, whereas death rates among CAPD patients have improved slightly (NS).

Uremic patients tend to have a lower than normal deep-body temperature. In addition, there is a clinical impression that uremic patients are also more thermolabile than healthy people; that is, in a warm environment, body temperature tends to be higher, and in a cold environment, body temperature tends to be lower than in healthy subjects. To test the hypothesis that uremia results in enhanced thermolability, nonoperated control (NO), nephrectomized (NX), and sham-nephrectomized (SHAM) rabbits were subjected to mild cold (5 degrees C) and heat (30 degrees C) stresses. At 48 hours postsurgery, the core temperature of NX rabbits was significantly lower than that of the NO or SHAM rabbits (P less than .01). Exposure to 5 degrees C resulted in a significant fall in body temperature of the NX (from 39.1 degrees C to 38.3 degrees C; P less than .05) rabbits compared to the NO rabbits. There was a tendency for body temperature of the SHAM rabbits to fall, and as a result, there was no significant difference in the change in body temperature between the SHAM and NX rabbits. Exposure to 30 degrees C resulted in virtually no change in the core temperature of the NO or SHAM rabbits, but did result in a significant rise in core temperature of the NX rabbits (P less than .02 and P less than .01 for respective comparisons), as well as a significant increase in mortality rate (P less than .02). Based on these data, we conclude that anephric animals are more thermolabile, and are less able to tolerate exposure to a warm environment, than are normal animals.

To evaluate the role of the dialysate in the stimulation of interleukin-1 (IL-1) production during clinical hemodialysis (HD), we studied maintenance HD patients in two experiments. Cellulosic hollow-fiber dialyzers were obtained after 20 minutes of HD using either nonsterile standard dialysate (n = 6) or sterile pyrogen free 0.9% saline as dialysate (n = 6). After rinsing the blood compartment with normal saline, dialyzers were incubated at 37 degrees C for six hours. Aliquots from the blood compartment were analyzed for the presence of IL-1 by (1) rabbit pyrogenic response after intravenous injection or (2) thymocyte co-proliferation assay. The in vivo assay showed a significantly greater febrile response when standard dialysate was used than in the sterile saline group (P less than .001), and this response could be abolished by heat inactivation of aliquots (P less than .001). The in vitro assay confirmed the presence of significantly greater amounts of IL-1 (P less than .05). Studies were repeated using filter sterilized standard dialysate (n = 6) v standard dialysate (n = 6) for 240 minutes of clinical HD. The in vitro assay revealed significantly lower IL-1 levels in the filtered sterilized dialysate group (P less than .05), however, a blank control assay showed yet significantly lower levels (P less than .05). We conclude that IL-1 is produced during clinical HD and that endotoxin or its fragments play a role in the stimulation of IL-1 production, probably through monocytes adhering to the dialysis membrane. In addition to this dialysate factor, IL-1 production appears also to be stimulated by a blood-membrane interaction.

Factors associated with physical well-being were examined in a population-based sample of adult end-stage renal disease (ESRD) patients in Michigan (n = 459). The dependent variables were two measures of physical functioning: (1) a ten-item measure of activities of daily living (ADL), and (2) the 45-item physical dysfunction dimension of the Sickness Impact Profile (SIP). Independent variables included four modalities of treatment (in-center hemodialysis, continuous ambulatory peritoneal dialysis [CAPD], related transplant, and cadaver transplant); primary cause of ESRD (eg, diabetes, glomerulonephritis); comorbidity (other illnesses besides primary cause of ESRD); and demographic characteristics (sex, race, age, marital status, education). ADL and SIP unadjusted mean scores differed significantly by category for each of the eight study factors (analysis of variance [ANOVA], P less than 0.0001), with the exception of sex for SIP means. The highest levels of dependency in ADL were reported by patients who were older, female, black, widowed, less educated, treated with in-center hemodialysis, had diabetes as the primary cause of ESRD, and/or reported more comorbidity. The partial effect of each factor on the dependent measures with adjustment for the seven other factors was assessed using analysis of covariance (ANCOVA). In the ADL analysis, sex, race, age, primary cause of kidney failure, and comorbidity were significant factors (probability values ranging from 0.05 for race to 0.0001 for sex, primary cause of ESRD, and comorbidity). The SIP physical dysfunction measure gave slightly different results. Race, age, primary cause of ESRD, comorbid status, and modality of treatment were significantly related to physical dysfunction (P less than 0.05 to P less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Cancer incidence was assessed in 4,161 end-stage renal disease (ESRD) patients on dialysis to determine whether there was any excess risk of cancer in this population. Records from the Michigan Kidney Registry (MKR) for 1973 to 1984 were linked to those of the Michigan Cancer Foundation's Metropolitan Detroit Cancer Surveillance System (MDCSS) to identify cases in the dialysis cohort. The expected number of cancers in the ESRD population was calculated using the race-, sex-, age- and calendar year-specific incidence rates of the tricounty metropolitan Detroit region of 4 million residents. The standardized incidence ratio (observed:expected) was significantly increased for all in situ tumors combined, as well as for invasive tumors of the kidney, the corpus uteri, and the prostate. The four-fold to five-fold excess (P less than 0.005) observed for renal and endometrial cancers, in addition to the significantly elevated (P less than 0.05) risk of prostate cancer indicates that patients maintained on dialysis should be evaluated for these tumors when they experience even minor symptoms. Population-based cancer and renal disease registries provide excellent opportunities for investigating etiologic hypotheses and future studies should incorporate potential risk factors when analyzing these data.